GISGISFundamentalsFundamentals

(Geographic Information Systems)

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Geographic

About the Earth

InformationDatabase, descriptions of things/objects

System Working together by using technology2

Defining Geographic Information Systems (GIS)

• The common ground between information processing and the many fields using spatial analysis techniques. (Tomlinson, 1972)

• A powerful set of tools for collecting, storing, retrieving, transforming, and displaying spatial data from the real world. (Burroughs, 1986)

• A computerized database management system for the capture, storage, retrieval, analysis and display of spatial (locationally defined) data. (NCGIA, 1987)

• A decision support system involving the integration of spatially referenced data in a problem solving environment. (Cowen, 1988)

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An Inelegant Definition for GIS

A system of integrated computer-based tools for end-to-end processing (capture, storage, retrieval, analysis,

display) of data using location on the earth’s surface for interrelation in support of operations management,

decision making, and science.

set of integrated tools for spatial analysisencompasses end-to-end processing of data

capture, storage, retrieval, analysis/modification, displayuses explicit location on earth’s surface to relate data

aimed at decision support, as well as on-going operations and scientific inquiry

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Geographic Information System: intuitive description

A map with a database behind it.A virtual representation of the real

world and its infrastructure. A consistent “as-built” of the real

world, natural and manmadeWhich is

queried to support on-going operations

summarized to support strategic decision making and policy

formulation analyzed to support scientific

inquiry

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How GIS differs from Related Systems

DBMS--typical MIS data base contains implicit but not explicit locational information

city, county, zip code, etc. but no geographical coordinatesis 100 N. High around the corner or across town from 200 E Main?

Automated mapping (AM) --primarily two-dimensional display devicesthematic mapping (choropleth, etc such as SAS/GRAPH, DIDS, business mapping software) unable to relate different geographical layers (eg zip

codes and counties)automated cartography--graphical design oriented; limited database ability

CAD/CAM (computer aided design/drafting)--primarily 3-D graphic creation (engineering design) & display systems

don’t reference via geographic locationCAD sees the world as a 3-D cube, GIS as a 3-D sphere

limited (if any) database ability (especially for non-spatial data)Scientific visualization systems--sophisticated multi-dimensional graphics,

But:lack database supportlack two-dimensional spatial analysis tools

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Where is it?(Find a specific address)

GIS Helps answer questions such as:

What else is nearby?(Hospital, gas station, fire station)

Where is the best location ? (Highest elevation )

What is the best route to reach specific locations?

Where is the closest ‘Z’ (shopping mall, School, Fire Hydrant) to my location?

WHY GIS?

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Why Study GIS?...........80% of local government activities estimated to be geographically based

plats, zoning, public works (streets, water supply, sewers), garbage collection, land ownership and valuation, public safety (fire and police)

a significant portion of provincial government has a geographical componentnatural resource managementhighways and transportation

businesses use GIS for a very wide array of applicationsretail site selection & customer analysis

logistics: vehicle tracking & routingnatural resource exploration (petroleum, etc.)

precision agriculturecivil engineering and construction

Military and defense Battlefield management

Satellite imagery interpretationscientific research employs GIS

geography, geology, botany anthropology, sociology, economics, political science

Epidemiology, criminology

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What GIS Applications Do:manage, analyze, communicate

• Make possible the automation of activities involving geographic datamap production

calculation of areas, distances, route lengthsmeasurement of slope, aspect, view shed

logistics: route planning, vehicle tracking, traffic management

• Allow for the integration of data (eg. property maps and air photos – Google earth has vector and

raster maps).

• By tying data to maps, permits the succinct communication of complex spatial patterns (eg environmental sensitivity).

• Provides answers to spatial queries (how many elderly in Richardson live further than 10 minutes at rush hour from ambulance service?)

• Perform complex spatial modeling (what if scenarios for transportation planning, disaster planning, resource management, utility design) 9

Data Collection

Real World

Data Input

Data Source

Take Action

Data Management

Analysis

Information For Decision making

Data Retrieval and Analysis

GIS System Architecture and Components

Start Next project

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Components of a GISThere are five components ........

People :People are the most important of a GIS because people must develop the procedures and define the task the GIS will perform

Data :Availability and accuracy of data affects the results of queries and analysis

Hardware :Hardware capabilities affect processing speed, ease of use and type of available output.

Software :Include GIS software, database, drawing, Images and other software programs

Procedures:GIS analysis requires well-define, consistent method to produce correct results

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Components of geographic dataThree main components to geographic data

Geometry : (Spatial)

Geometry represent the geographic feature associate with real-world locations1. Point 2. line 3. polygons (areas)

Attributes: (Non Spatial)

Attributes are descriptive characteristics of the geographic feature . Name, Length, size, colour,

Behaviour:Behaviour means that geographic features can be made to allow certain types of editing, display or analysis.

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How a GIS organizes geographic data

• Stores information about the world as a collection of thematic layers that can be link by geography

• Each layer contains feature having similar attributes Eg : Streets or cities that are located within same geographic extent

The layer all contain features located within the city boundaries, but each one represents distinct “theme”

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How does it work?

• Each layer of information has two components

1. Spatial ( x, y coordinate, Location of the earth)2. Non-Spatial (Attributes, description of the data location)

• Software orient map on the screen according to X, Y coordinates

• If another layer possesses the same coordinates * if will be drawn in the same relative location on the screen * Layer can then be seen relative to one another

In this map of South America, countries are represented as polygons, rivers are represented as lines, and cities are points

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Examples of Applied GIS• Civil Engineering/Utility

– Locating underground facilities– Designing alignment for freeways, transit– Coordination of infrastructure maintenance

• Business– Demographic Analysis– Market Penetration/ Share Analysis– Site Selection

• Education Administration– Attendance Area Maintenance– Enrollment Projections– School Bus Routing

• Real Estate– Neighborhood land prices– Traffic Impact Analysis– Determination of Highest and Best Use

• Health Care– Epidemiology– Needs Analysis– Service Inventory

Urban Planning, Management & Policy -Zoning, subdivision planning

- Land acquisition- Economic development

- Code enforcement- Housing renovation programs

- Emergency response- Crime analysis

- Tax assessmentEnvironmental Sciences- Monitoring environmental risk- Modeling storm water runoff

- Management of watersheds, floodplains, wetlands, forests, aquifers

- Environmental Impact Analysis- Hazardous or toxic facility siting

-Groundwater modeling and - contamination trackingPolitical Science

- Redistricting- Analysis of election results

- Predictive modeling

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Agriculture

Farm managementPest/Disease tracking

Crop monitoringYield prediction

Soil analysis

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Natural Resource Management

• Forestry• Ecology• Mining• Petroleum• Water Resources

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Planning and Economic Development

• Land Use/Zoning• Emergency Preparedness• Population Forecast• Market Analysis• Property Tax Assessment• Transportation

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